Four Derivative Spectrophotometric Methods for the Simultaneous Determination of Carmoisine and Ponceau 4R in Drinks and Comparison with High Performance Liquid Chromatography

Figure 3

Difference absorption spectra of 10 μg mL⁻¹ Carmoisine, 10 μg mL⁻¹ Ponceau 4R and their binary mixture (a). Difference first derivative spectra (b) of colorants (Carmoisine: 2–10 μg mL⁻¹; Ponceau 4R: 2–10 μg mL⁻¹).

(a)

(b)